This invention relates to an endoscope which is inserted into a body cavity such as a heart, a blood vessel and a tubular body cavity including bled blood or an opaque body fluid and with which an operator can treat an affected portion in the body cavity while he is observing the interior of the tubular body cavity in spite of the blood or other body fluid.
As shown in FIG. 1, a known endoscope such as a cardiofiberscope used in a tubular body cavity containing blood or other body fluid comprises a distal end section 1, an observation optical system 2 and as illumination system 3 both disposed in the section 1 and a transparent cuff 4 attached to the free end of the section 1. The cuff 4 communicates with an air channel 5 and is inflated with air supplied through the air channel 5. When inflated, the cuff 4 contacts the inner surface of a tubular body cavity, thus expelling or clearing blood or other body fluid from the space between the illumination optical system 2 and the illumination system 3 and the inner surface of the tubular body cavity. This allows an operator to observe the inner surface of the body cavity without blur due to the blood or other body fluid.
Indeed it is possible with the prior art endoscope to observe the inner surface of a tubular body cavity. But it is impossible with it to use a medical instrument such as forceps and thus to pick up tissues from the body cavity or stop bleeding in the body cavity.